This application claims priority back to Italian Application No MI 2012 A 001137 filed on Jun. 28, 2012, which is hereby incorporated by reference

FIELD

The present invention concerns a bending core to bend filiform materials like pipes. Said core comprises two or more component parts put in series to each other. Said component parts feature a shape suitable for engaging the complete portion of the inner area of the surface of the pipe being bent to prevent the formation of folds in the inner portion of the pipe being bent, thus preventing the material being deformed from folding instead of following a curvilinear pattern.

BACKGROUND OF THE INVENTION

A typical method to bend a pipe consists of using a bending core to prevent and reduce folds in the inner portion of the bent pipe. Ideally, the bending core should have such a shape as to constantly adhere to the inner wall of the pipe being bent, so as to prevent the formation of folds in such inner wall during the mentioned bending step.

The shapes of the bending core known are numerous. Concerning the bending core that is the object of the present patent application, bending cores formed of several component parts connected in series to each other are to be considered as known. However, a drawback of said known bending cores consists in that they always leave an empty space between one component part and the other, as one might notice by examining the figures of the Japanese patent applications JP 2005205483 A and JP 2009172661 as well as the document EP 1 488 867 which describes and shows a mandrel for bending a simple construction and sufficient rigidity like a pipe comprising a plurality of plugs. Each plug is provided with a spherical outer peripheral surface.

DISCLOSURE OF THE INVENTION

The bending core that is the subject of the present patent application advantageously solves the problems of the known technique by providing a bending core to bend filiform materials, for instance a pipe, comprising two or more component parts connected in series to each other. Each of said component parts comprises an outer portion having a spheroidal shape suitable for engaging the complete area between the inner wall of the pipe being bent as well as the outer surface of the portion of the component part that precedes it. Such a positioning is possible for all component parts present along the bending line of the pipe, because said component parts have a spheroidal shape with at least one longitudinal section of at least one external profile having a plane curvilinear shape. According to a first embodiment, the external profile of each component part that makes up the subject bending core and having a plane curvilinear shape comprises at least one first convex curve and preferably at least one second concave curve. According to a second embodiment, the shape of each component part making up the mentioned core differs from the embodiment described above in the external profile of the component part. It comprises at least one portion having the shape like the tangent function of said external profile whose plane curvilinear profile, referred to as tangent function here below, is suitable for connecting said first convex curve and said second concave curve continuously.

It is evident that the mentioned tangent function could be reduced down to describe just an inflexion point between the two curves, which would mean, in this case, to go back to said first embodiment described above. to Each component part of the subject bending core is connected to another component part by means of a multidirectional hooking device comprising a sphere coupled with an elastic mechanical member having the shape of a saddle, suitable for hooking the sphere of the other component part it hooks to.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a longitudinal section view of the subject bending core assembly.

FIG. 1 bis shows a longitudinal section view of a single component part that, joined to others identical thereto, makes up the subject bending core.

FIG. 2 shows a longitudinal section view of the external profile of the first embodiment of the component part that, joined to others identical thereto, makes up the subject bending core.

FIG. 3 shows a longitudinal section view of the external profile of the second embodiment of the component part that, joined to others identical thereto, makes up the subject bending core.

FIG. 1 shows a longitudinal section view of the bending core assembly (1) to bend filiform materials, for instance a pipe (2), comprising two or more component parts (3) connected in series to each other. Each of said component parts (3) comprises an external portion (4) having a spheroidal shape suitable for engaging the complete area between the inner wall (P) of the pipe (2) being bent. The outer surface (5) of the portion (4) of the component part (3) is suitable for overlapping the corresponding surface (5) of the portion (4) of another component part (3) that precedes it along the bending line (S). Said portion (4) is suitable for engaging the complete area between the inner wall (P) of the pipe (2) being bent because it features a spheroidal shape, at least one longitudinal section (6) of at least one external profile (7) having a plane curvilinear shape (8).

FIG. 1 also shows the element used to interconnect the individual component parts (3). Each of said component parts (3) is connected to another component part (3) by means of a multidirectional hooking device (12), not shown in this figure, comprising a sphere (13), coupled with an elastic mechanical member (14) having the shape of a saddle suitable for hooking the sphere (13) of said other component part (3).

FIG. 1 bis shows a longitudinal section view of a single component part (3) that, joined to others identical thereto, makes up the subject bending core. Said component part (3) comprises an external portion (4) having a spheroidal shape. This portion (4), as shown in FIG. 1, is suitable for engaging the complete area between the inner wall (P) of the pipe (2) being bent. Said component part (3) also comprises a multidirectional hooking device (12) which comprises a sphere (13) coupled with an elastic mechanical member (14) having the shape of a saddle. This elastic mechanical member (14) is suitable for hooking the sphere (13) of another component part (3) that follows it so that, by joining several component parts (3) together in this manner, the bending core (1) is formed.

FIG. 2 shows a longitudinal section view of the external profile of the first embodiment of the component part that, joined to others identical thereto, makes up the subject bending core. Said external profile (7) having a plane curvilinear shape (8) features a first convex curve (9) and a second concave curve (10).

FIG. 3 shows a longitudinal section view of the external profile of the second embodiment of the component part that, joined to others identical thereto, makes up the subject bending core. Said external profile (7) having a plane curvilinear shape (8) comprises at least one tangent function (11) suitable for connecting said first convex curve (9) and said second concave curve (10) continuously. Said tangent function (11) is represented in FIG. 3, by way of an example, by a segment.